The invention relates to a receiving arrangement of a motor vehicle having a first antenna array disposed at or on the body of the motor vehicle, and having a second antenna array disposed on a window pane of the motor vehicle. The antenna arrays are coupled to a joint receiving unit for the further processing of the received signals, in particular, for their demodulation and/or decoding.
In the case of current receiving arrangements of the above-mentioned type, respective antenna amplifiers are assigned to the first antenna array and to the second antenna array. The amplifiers are arranged together with the assigned antenna in a respective antenna array. For reasons of cost, a joint receiver or several receivers in an array or in a housing are assigned to both antennas or both antenna arrays. Together with a CD-drive, an optional navigation system and additional components, this receiver is arranged in a control unit (a so-called “head unit”) of the motor vehicle, which is typically situated in the area of the instrument panel of the motor vehicle (or in another location, for example, in the luggage compartment).
The first antenna array is normally arranged in the shape of a fin with or without a placed rod antenna on the roof of the motor vehicle. The antenna amplifier may be arranged in the fin or on the roof of the vehicle body. The first antenna array frequently includes a plurality of antennas for receiving respective short-wave radio services. In particular, these are the reception of digital audio signals (DAB—Digital Audio Broadcasting), navigation data (GPS—Global Positioning System), telephone, as well as optionally—when a rod antenna is present—analog audio signals in the FM and AM band, for example, for antenna diversity applications.
The second antenna array frequently also includes several antennas for different applications. The antenna or antennas of the second antenna array are usually arranged on the rear window and/or a side window of the motor vehicle. They are provided for the reception of long-wave radio services, particularly therefore for the reception of analog audio signals in the FM and AM band as well as the reception of video data (TV). The antenna amplifier of the second antenna array is normally invisibly accommodated in the area of the window pane or a vehicle body component adjoining the window pane.
The antenna arrays are connected with the spatially remote receiver by way of shielded lines which in some cases have a length of several meters. As a rule, coaxial cables are used for this purpose. A separate shielded line is to be provided for each antenna of an antenna array.
The described arrangement is expensive and its constructive expenditures are high because of the necessity of using a plurality of shielded lines and because of the necessity of amplifying the signals received by the antenna array before the transmission to the receiver.
It therefore is an object of the present invention to provide a receiving arrangement that has a constructively simpler structure and can be produced in a more cost-effective manner.
This and other objects are achieved by a receiving arrangement of a motor vehicle having a first antenna array disposed at or on the body of the motor vehicle, and having a second antenna array disposed on a window pane of the motor vehicle, the antennas being coupled to a receiving unit for the further processing, particularly for the demodulation and/or decoding, of a respective received signal of the antennas. In this receiving arrangement, the receiving unit having a number of receivers is directly connected with the first and the second antenna array. During operation, the receiving unit causes a conversion of a respective received signal of the antennas to a respective loss-free transportable digital signal.
In the context of the present specification, a “direct connection” of the first or second antenna array with the receiving unit is a coaxial-cable-free connection or a connection without coaxial-cable plug-in connectors.
Furthermore, a direct connection means that the receiving unit with the number of receivers is arranged in the immediate spatial proximity of the first antenna array and of the second antenna array.
On the one hand, this arrangement makes it possible to do without the shielded lines. Shielded lines are required neither between the first and the second antenna array and the receiving unit, nor between the receiving unit and the control unit. As a result, the cabling of the receiving arrangement can have a simpler construction. The direct connection of the first and second antenna array to the receiving unit of the receiving arrangement further permits the elimination of the antenna amplifiers customary in the state of the art. On the one hand, this reduces the system costs of the receiving arrangement. Furthermore, space and weight can be saved.
The receiving unit, which according to the invention is linked directly to the first and the second antenna array, comprises a signal converter which converts received HF signals to a digital loss-free and transportable signal. When the signals received from the first or the second antenna array are present in digital form, these can be transmitted in a loss-free manner by way of a single cable to the remotely arranged control unit of the receiving unit.
According to one embodiment, an analog high-frequency (HF) signal is transmitted during the operation by way of a direct connection between the first antenna array and the receiving unit, as well as the second antenna array and the receiving unit. As a result of the direct connection between the first antenna array and the receiving unit or the second antenna array and the receiving unit, it is not necessary to shield the direct connection and to provide a normally used coaxial cable. Because of the direct connection, lower losses will occur up to the conversion of the received signals in the receiving unit to digital signals. The antenna amplifiers normally provided in spatial proximity of the antennas are therefore also not required.
In a further aspect of the invention, the receiving unit is connected with the first antenna array by way of a first ribbon cable and with the second antenna array by way of a second ribbon cable. The use of ribbon cables for generating a direct connection has the advantage that correct impedance replica can be obtained by use of the ribbon cables.
In a further embodiment, the length of the direct connection between the first antenna array and the receiving unit amounts to less than 10 cm, preferably less than 5 cm. In an advantageous further development, the length of the direct connection between the second antenna array and the receiving unit amounts to less than 20 cm, preferably less than 10 cm.
In another alternative further development, the receiving unit is connected with the first antenna array by way of a first plug and with the second antenna array by way of a second plug. In this embodiment, the receiving unit is arranged in the motor vehicle in the area of the first and second antenna array such that a wireless connection to the antennas becomes possible.
For this purpose, it may be provided that the receiving unit and the first antenna array are arranged on the roof of the body of the motor vehicle. It may further be provided that the plurality of receivers is arranged in a common housing, for example, on the roof of the motor vehicle.
According to a still further embodiment, the first and/or the second antenna array have several antennas for different receiving purposes, one receiver of the receiving unit being assigned to each antenna of the first and the second antenna array. In other words, the receiving unit has at least two receivers, one of the receivers being assigned to the first antenna array and the other being assigned to the second antenna array. Furthermore, the receiving unit may include additional receivers which are assigned to respective specific antennas of the first and second antenna array.
The first antenna array preferably has antennas for receiving radio services in the frequency range above 700 MHz (with a rod for receiving analog audio signals (FM/AM), also frequencies starting from 150 kHz), particularly for receiving digital audio signals (DAB), navigation data, and telephone. The second antenna array preferably has antennas for receiving radio services in the frequency range of between 150 kHz and 900 MHz, particularly for receiving analog audio signals (FM/AM) and video data (TV).
According to a further embodiment, the receiving unit and the control unit may be mutually connected by way of a bus, by which the respective digitized signal of the first and second antenna array can be transmitted. It is not relevant with respect to the invention on which technical principle the bus is based. Any known bus, for example, an Ethernet bus, can therefore be used.
According to a further suitable embodiment, the control unit is provided in a head unit of the motor vehicle. The components required for the demodulation and/or decoding may be combined in a central array (head unit) together with other communication and entertainment components or be provided in the receiving unit. In principle, it is also contemplated to arrange the individual elements of the receiving unit in different arrays. Thus, the demodulation (or decoding) could, for example, spatially already take place in the receiving unit. The further signal conversion could then be carried out after the transmission of the corresponding digital signals in a component arranged in the control unit or connected with the latter.
Because of the elimination of shielded high-frequency lines, the invention permits a simplification of the topology of a receiving arrangement for a motor vehicle. As a result, particularly significant cost reductions can be achieved.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.